An I/O controller for virtual pinball machines: accelerometer nudge sensing, analog plunger input, button input encoding, LedWiz compatible output controls, and more.

Dependencies:   mbed FastIO FastPWM USBDevice

Fork of Pinscape_Controller by Mike R

/media/uploads/mjr/pinscape_no_background_small_L7Miwr6.jpg

This is Version 2 of the Pinscape Controller, an I/O controller for virtual pinball machines. (You can find the old version 1 software here.) Pinscape is software for the KL25Z that turns the board into a full-featured I/O controller for virtual pinball, with support for accelerometer-based nudging, a mechanical plunger, button inputs, and feedback device control.

In case you haven't heard of the idea before, a "virtual pinball machine" is basically a video pinball simulator that's built into a real pinball machine body. A TV monitor goes in place of the pinball playfield, and a second TV goes in the backbox to show the backglass artwork. Some cabs also include a third monitor to simulate the DMD (Dot Matrix Display) used for scoring on 1990s machines, or even an original plasma DMD. A computer (usually a Windows PC) is hidden inside the cabinet, running pinball emulation software that displays a life-sized playfield on the main TV. The cabinet has all of the usual buttons, too, so it not only looks like the real thing, but plays like it too. That's a picture of my own machine to the right. On the outside, it's built exactly like a real arcade pinball machine, with the same overall dimensions and all of the standard pinball cabinet trim hardware.

It's possible to buy a pre-built virtual pinball machine, but it also makes a great DIY project. If you have some basic wood-working skills and know your way around PCs, you can build one from scratch. The computer part is just an ordinary Windows PC, and all of the pinball emulation can be built out of free, open-source software. In that spirit, the Pinscape Controller is an open-source software/hardware project that offers a no-compromises, all-in-one control center for all of the unique input/output needs of a virtual pinball cabinet. If you've been thinking about building one of these, but you're not sure how to connect a plunger, flipper buttons, lights, nudge sensor, and whatever else you can think of, this project might be just what you're looking for.

You can find much more information about DIY Pin Cab building in general in the Virtual Cabinet Forum on vpforums.org. Also visit my Pinscape Resources page for more about this project and other virtual pinball projects I'm working on.

Downloads

  • Pinscape Release Builds: This page has download links for all of the Pinscape software. To get started, install and run the Pinscape Config Tool on your Windows computer. It will lead you through the steps for installing the Pinscape firmware on the KL25Z.
  • Config Tool Source Code. The complete C# source code for the config tool. You don't need this to run the tool, but it's available if you want to customize anything or see how it works inside.

Documentation

The new Version 2 Build Guide is now complete! This new version aims to be a complete guide to building a virtual pinball machine, including not only the Pinscape elements but all of the basics, from sourcing parts to building all of the hardware.

You can also refer to the original Hardware Build Guide (PDF), but that's out of date now, since it refers to the old version 1 software, which was rather different (especially when it comes to configuration).

System Requirements

The new Config Tool requires a fairly up-to-date Microsoft .NET installation. If you use Windows Update to keep your system current, you should be fine. A modern version of Internet Explorer (IE) is required, even if you don't use it as your main browser, because the Config Tool uses some system components that Microsoft packages into the IE install set. I test with IE11, so that's known to work. IE8 doesn't work. IE9 and 10 are unknown at this point.

The Windows requirements are only for the config tool. The firmware doesn't care about anything on the Windows side, so if you can make do without the config tool, you can use almost any Windows setup.

Main Features

Plunger: The Pinscape Controller started out as a "mechanical plunger" controller: a device for attaching a real pinball plunger to the video game software so that you could launch the ball the natural way. This is still, of course, a central feature of the project. The software supports several types of sensors: a high-resolution optical sensor (which works by essentially taking pictures of the plunger as it moves); a slide potentiometer (which determines the position via the changing electrical resistance in the pot); a quadrature sensor (which counts bars printed on a special guide rail that it moves along); and an IR distance sensor (which determines the position by sending pulses of light at the plunger and measuring the round-trip travel time). The Build Guide explains how to set up each type of sensor.

Nudging: The KL25Z (the little microcontroller that the software runs on) has a built-in accelerometer. The Pinscape software uses it to sense when you nudge the cabinet, and feeds the acceleration data to the pinball software on the PC. This turns physical nudges into virtual English on the ball. The accelerometer is quite sensitive and accurate, so we can measure the difference between little bumps and hard shoves, and everything in between. The result is natural and immersive.

Buttons: You can wire real pinball buttons to the KL25Z, and the software will translate the buttons into PC input. You have the option to map each button to a keyboard key or joystick button. You can wire up your flipper buttons, Magna Save buttons, Start button, coin slots, operator buttons, and whatever else you need.

Feedback devices: You can also attach "feedback devices" to the KL25Z. Feedback devices are things that create tactile, sound, and lighting effects in sync with the game action. The most popular PC pinball emulators know how to address a wide variety of these devices, and know how to match them to on-screen action in each virtual table. You just need an I/O controller that translates commands from the PC into electrical signals that turn the devices on and off. The Pinscape Controller can do that for you.

Expansion Boards

There are two main ways to run the Pinscape Controller: standalone, or using the "expansion boards".

In the basic standalone setup, you just need the KL25Z, plus whatever buttons, sensors, and feedback devices you want to attach to it. This mode lets you take advantage of everything the software can do, but for some features, you'll have to build some ad hoc external circuitry to interface external devices with the KL25Z. The Build Guide has detailed plans for exactly what you need to build.

The other option is the Pinscape Expansion Boards. The expansion boards are a companion project, which is also totally free and open-source, that provides Printed Circuit Board (PCB) layouts that are designed specifically to work with the Pinscape software. The PCB designs are in the widely used EAGLE format, which many PCB manufacturers can turn directly into physical boards for you. The expansion boards organize all of the external connections more neatly than on the standalone KL25Z, and they add all of the interface circuitry needed for all of the advanced software functions. The big thing they bring to the table is lots of high-power outputs. The boards provide a modular system that lets you add boards to add more outputs. If you opt for the basic core setup, you'll have enough outputs for all of the toys in a really well-equipped cabinet. If your ambitions go beyond merely well-equipped and run to the ridiculously extravagant, just add an extra board or two. The modular design also means that you can add to the system over time.

Expansion Board project page

Update notes

If you have a Pinscape V1 setup already installed, you should be able to switch to the new version pretty seamlessly. There are just a couple of things to be aware of.

First, the "configuration" procedure is completely different in the new version. Way better and way easier, but it's not what you're used to from V1. In V1, you had to edit the project source code and compile your own custom version of the program. No more! With V2, you simply install the standard, pre-compiled .bin file, and select options using the Pinscape Config Tool on Windows.

Second, if you're using the TSL1410R optical sensor for your plunger, there's a chance you'll need to boost your light source's brightness a little bit. The "shutter speed" is faster in this version, which means that it doesn't spend as much time collecting light per frame as before. The software actually does "auto exposure" adaptation on every frame, so the increased shutter speed really shouldn't bother it, but it does require a certain minimum level of contrast, which requires a certain minimal level of lighting. Check the plunger viewer in the setup tool if you have any problems; if the image looks totally dark, try increasing the light level to see if that helps.

New Features

V2 has numerous new features. Here are some of the highlights...

Dynamic configuration: as explained above, configuration is now handled through the Config Tool on Windows. It's no longer necessary to edit the source code or compile your own modified binary.

Improved plunger sensing: the software now reads the TSL1410R optical sensor about 15x faster than it did before. This allows reading the sensor at full resolution (400dpi), about 400 times per second. The faster frame rate makes a big difference in how accurately we can read the plunger position during the fast motion of a release, which allows for more precise position sensing and faster response. The differences aren't dramatic, since the sensing was already pretty good even with the slower V1 scan rate, but you might notice a little better precision in tricky skill shots.

Keyboard keys: button inputs can now be mapped to keyboard keys. The joystick button option is still available as well, of course. Keyboard keys have the advantage of being closer to universal for PC pinball software: some pinball software can be set up to take joystick input, but nearly all PC pinball emulators can take keyboard input, and nearly all of them use the same key mappings.

Local shift button: one physical button can be designed as the local shift button. This works like a Shift button on a keyboard, but with cabinet buttons. It allows each physical button on the cabinet to have two PC keys assigned, one normal and one shifted. Hold down the local shift button, then press another key, and the other key's shifted key mapping is sent to the PC. The shift button can have a regular key mapping of its own as well, so it can do double duty. The shift feature lets you access more functions without cluttering your cabinet with extra buttons. It's especially nice for less frequently used functions like adjusting the volume or activating night mode.

Night mode: the output controller has a new "night mode" option, which lets you turn off all of your noisy devices with a single button, switch, or PC command. You can designate individual ports as noisy or not. Night mode only disables the noisemakers, so you still get the benefit of your flashers, button lights, and other quiet devices. This lets you play late into the night without disturbing your housemates or neighbors.

Gamma correction: you can designate individual output ports for gamma correction. This adjusts the intensity level of an output to make it match the way the human eye perceives brightness, so that fades and color mixes look more natural in lighting devices. You can apply this to individual ports, so that it only affects ports that actually have lights of some kind attached.

IR Remote Control: the controller software can transmit and/or receive IR remote control commands if you attach appropriate parts (an IR LED to send, an IR sensor chip to receive). This can be used to turn on your TV(s) when the system powers on, if they don't turn on automatically, and for any other functions you can think of requiring IR send/receive capabilities. You can assign IR commands to cabinet buttons, so that pressing a button on your cabinet sends a remote control command from the attached IR LED, and you can have the controller generate virtual key presses on your PC in response to received IR commands. If you have the IR sensor attached, the system can use it to learn commands from your existing remotes.

Yet more USB fixes: I've been gradually finding and fixing USB bugs in the mbed library for months now. This version has all of the fixes of the last couple of releases, of course, plus some new ones. It also has a new "last resort" feature, since there always seems to be "just one more" USB bug. The last resort is that you can tell the device to automatically reboot itself if it loses the USB connection and can't restore it within a given time limit.

More Downloads

  • Custom VP builds: I created modified versions of Visual Pinball 9.9 and Physmod5 that you might want to use in combination with this controller. The modified versions have special handling for plunger calibration specific to the Pinscape Controller, as well as some enhancements to the nudge physics. If you're not using the plunger, you might still want it for the nudge improvements. The modified version also works with any other input controller, so you can get the enhanced nudging effects even if you're using a different plunger/nudge kit. The big change in the modified versions is a "filter" for accelerometer input that's designed to make the response to cabinet nudges more realistic. It also makes the response more subdued than in the standard VP, so it's not to everyone's taste. The downloads include both the updated executables and the source code changes, in case you want to merge the changes into your own custom version(s).

    Note! These features are now standard in the official VP releases, so you don't need my custom builds if you're using 9.9.1 or later and/or VP 10. I don't think there's any reason to use my versions instead of the latest official ones, and in fact I'd encourage you to use the official releases since they're more up to date, but I'm leaving my builds available just in case. In the official versions, look for the checkbox "Enable Nudge Filter" in the Keys preferences dialog. My custom versions don't include that checkbox; they just enable the filter unconditionally.
  • Output circuit shopping list: This is a saved shopping cart at mouser.com with the parts needed to build one copy of the high-power output circuit for the LedWiz emulator feature, for use with the standalone KL25Z (that is, without the expansion boards). The quantities in the cart are for one output channel, so if you want N outputs, simply multiply the quantities by the N, with one exception: you only need one ULN2803 transistor array chip for each eight output circuits. If you're using the expansion boards, you won't need any of this, since the boards provide their own high-power outputs.
  • Cary Owens' optical sensor housing: A 3D-printable design for a housing/mounting bracket for the optical plunger sensor, designed by Cary Owens. This makes it easy to mount the sensor.
  • Lemming77's potentiometer mounting bracket and shooter rod connecter: Sketchup designs for 3D-printable parts for mounting a slide potentiometer as the plunger sensor. These were designed for a particular slide potentiometer that used to be available from an Aliexpress.com seller but is no longer listed. You can probably use this design as a starting point for other similar devices; just check the dimensions before committing the design to plastic.

Copyright and License

The Pinscape firmware is copyright 2014, 2021 by Michael J Roberts. It's released under an MIT open-source license. See License.

Warning to VirtuaPin Kit Owners

This software isn't designed as a replacement for the VirtuaPin plunger kit's firmware. If you bought the VirtuaPin kit, I recommend that you don't install this software. The KL25Z can only run one firmware program at a time, so if you install the Pinscape firmware on your KL25Z, it will replace and erase your existing VirtuaPin proprietary firmware. If you do this, the only way to restore your VirtuaPin firmware is to physically ship the KL25Z back to VirtuaPin and ask them to re-flash it. They don't allow you to do this at home, and they don't even allow you to back up your firmware, since they want to protect their proprietary software from copying. For all of these reasons, if you want to run the Pinscape software, I strongly recommend that you buy a "blank" retail KL25Z to use with Pinscape. They only cost about $15 and are available at several online retailers, including Amazon, Mouser, and eBay. The blank retail boards don't come with any proprietary firmware pre-installed, so installing Pinscape won't delete anything that you paid extra for.

With those warnings in mind, if you're absolutely sure that you don't mind permanently erasing your VirtuaPin firmware, it is at least possible to use Pinscape as a replacement for the VirtuaPin firmware. Pinscape uses the same button wiring conventions as the VirtuaPin setup, so you can keep your buttons (although you'll have to update the GPIO pin mappings in the Config Tool to match your physical wiring). As of the June, 2021 firmware, the Vishay VCNL4010 plunger sensor that comes with the VirtuaPin v3 plunger kit is supported, so you can also keep your plunger, if you have that chip. (You should check to be sure that's the sensor chip you have before committing to this route, if keeping the plunger sensor is important to you. The older VirtuaPin plunger kits came with different IR sensors that the Pinscape software doesn't handle.)

Committer:
mjr
Date:
Thu Jan 23 04:09:24 2020 +0000
Revision:
105:6a25bbfae1e4
Parent:
103:dec22cd65b2a
Child:
106:e9e3b46132c1
Fix AEDR-8300 reverse orientation option

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 100:1ff35c07217c 1 // Plunger sensor implementation for rotary absolute encoders
mjr 100:1ff35c07217c 2 //
mjr 100:1ff35c07217c 3 // This implements the plunger interfaces for rotary absolute encoders. A
mjr 100:1ff35c07217c 4 // rotary encoder measures the angle of a rotating shaft. For plunger sensing,
mjr 100:1ff35c07217c 5 // we can convert the plunger's linear motion into angular motion using a
mjr 100:1ff35c07217c 6 // mechanical linkage between the plunger rod and a rotating shaft positioned
mjr 100:1ff35c07217c 7 // at a fixed point, somewhere nearby, but off of the plunger's axis:
mjr 100:1ff35c07217c 8 //
mjr 100:1ff35c07217c 9 // =X=======================|=== <- plunger, X = connector attachment point
mjr 100:1ff35c07217c 10 // \
mjr 100:1ff35c07217c 11 // \ <- connector between plunger and shaft
mjr 100:1ff35c07217c 12 // \
mjr 100:1ff35c07217c 13 // * <- rotating shaft, at a fixed position
mjr 100:1ff35c07217c 14 //
mjr 100:1ff35c07217c 15 // As the plunger moves, the angle of the connector relative to the fixed
mjr 100:1ff35c07217c 16 // shaft position changes in a predictable way, so by measuring the rotational
mjr 100:1ff35c07217c 17 // position of the shaft at any given time, we can infer the plunger's
mjr 100:1ff35c07217c 18 // linear position.
mjr 100:1ff35c07217c 19 //
mjr 100:1ff35c07217c 20 // (Note that the mechanical diagram is simplified for ASCII art purposes.
mjr 100:1ff35c07217c 21 // What's not shown is that the distance between the rotating shaft and the
mjr 100:1ff35c07217c 22 // "X" connection point on the plunger varies as the plunger moves, so the
mjr 100:1ff35c07217c 23 // mechanical linkage requires some way to accommodate that changing length.
mjr 100:1ff35c07217c 24 // One way is to use a spring as the linkage; another is to use a rigid
mjr 100:1ff35c07217c 25 // connector with a sliding coupling at one or the other end. We leave
mjr 100:1ff35c07217c 26 // these details up to the mechanical design; the software isn't affected
mjr 100:1ff35c07217c 27 // as long as the basic relationship between linear and angular motion as
mjr 100:1ff35c07217c 28 // shown in the diagram be achieved.)
mjr 100:1ff35c07217c 29 //
mjr 100:1ff35c07217c 30 //
mjr 100:1ff35c07217c 31 // Translating the angle to a linear position
mjr 100:1ff35c07217c 32 //
mjr 100:1ff35c07217c 33 // There are two complications to translating the angular reading back to
mjr 100:1ff35c07217c 34 // a linear plunger position.
mjr 100:1ff35c07217c 35 //
mjr 100:1ff35c07217c 36 // 1. We have to consider the sensor's zero point to be arbitrary. That means
mjr 100:1ff35c07217c 37 // that the zero point could be somewhere within the plunger's travel range,
mjr 100:1ff35c07217c 38 // so readings might "wrap" - e.g., we might see a series of readings when
mjr 100:1ff35c07217c 39 // the plunger is moving in one direction like 4050, 4070, 4090, 14, 34 (note
mjr 100:1ff35c07217c 40 // how we've "wrapped" past the 4096 boundary).
mjr 100:1ff35c07217c 41 //
mjr 100:1ff35c07217c 42 // To deal with this, we have to make a couple of assumptions:
mjr 100:1ff35c07217c 43 //
mjr 100:1ff35c07217c 44 // - The park position is at about 1/6 of the overall travel range
mjr 100:1ff35c07217c 45 // - The total angular travel range is less than one full revolution
mjr 100:1ff35c07217c 46 //
mjr 100:1ff35c07217c 47 // With those assumptions in hand, we can bias the raw readings to the
mjr 100:1ff35c07217c 48 // park position, and then take them modulo the raw scale. That will
mjr 100:1ff35c07217c 49 // ensure that readings wrap properly, regardless of where the raw zero
mjr 100:1ff35c07217c 50 // point lies.
mjr 100:1ff35c07217c 51 //
mjr 103:dec22cd65b2a 52 // 2. Going back to the original diagram, you can see that there's some
mjr 103:dec22cd65b2a 53 // trigonometry required to interpret the sensor's angular reading as a
mjr 103:dec22cd65b2a 54 // linear position on the plunger axis, which is of course what we need
mjr 103:dec22cd65b2a 55 // to report to the PC software.
mjr 103:dec22cd65b2a 56 //
mjr 103:dec22cd65b2a 57 // Let's use the vertical line between the plunger and the rotation point
mjr 103:dec22cd65b2a 58 // as the zero-degree reference point. To figure the plunger position,
mjr 100:1ff35c07217c 59 // we need to figure the difference between the raw angle reading and the
mjr 100:1ff35c07217c 60 // zero-degree point; call this theta. Let L be the position of the plunger
mjr 100:1ff35c07217c 61 // relative to the vertical reference point, let D be the length of the
mjr 100:1ff35c07217c 62 // vertical reference point line, and let H by the distance from the rotation
mjr 100:1ff35c07217c 63 // point to the plunger connection point. This is a right triangle with
mjr 100:1ff35c07217c 64 // hypotenuse H and sides L and D. D is a constant, because the rotation
mjr 100:1ff35c07217c 65 // point never moves, and the plunger never moves vertically. Thus we can
mjr 100:1ff35c07217c 66 // calculate D = H*cos(theta) and L = H*sin(theta). D is a constant, so
mjr 100:1ff35c07217c 67 // we can figure H = D/cos(theta) hence L = D*sin(theta)/cos(theta) or
mjr 100:1ff35c07217c 68 // D*tan(theta). If we wanted to know the true position in real-world
mjr 100:1ff35c07217c 69 // units, we'd have to know D, but only need arbitrary linear units, so
mjr 100:1ff35c07217c 70 // we can choose whatever value for D we find convenient: in particular,
mjr 100:1ff35c07217c 71 // a value that gives us the desired range and resolution for the final
mjr 100:1ff35c07217c 72 // result.
mjr 100:1ff35c07217c 73 //
mjr 103:dec22cd65b2a 74 // Note that the tangent diverges at +/-90 degrees, but that's okay,
mjr 103:dec22cd65b2a 75 // because the mechanical setup we've described is inherently constrained
mjr 103:dec22cd65b2a 76 // to stay well within those limits. This would even be true for an
mjr 103:dec22cd65b2a 77 // arbitrarily long range of motion along the travel axis, but we don't
mjr 103:dec22cd65b2a 78 // even have to worry about that since we have such a well-defined range
mjr 103:dec22cd65b2a 79 // of travel (of only about 3") to track.
mjr 100:1ff35c07217c 80 //
mjr 100:1ff35c07217c 81 // There's still one big piece missing here: we somehow have to know where
mjr 100:1ff35c07217c 82 // that vertical zero point lies. That's something we can only learn by
mjr 100:1ff35c07217c 83 // calibration. Unfortunately, we don't have a good way to detect this
mjr 100:1ff35c07217c 84 // directly. We *could* ask the user to look inside the cabinet and press
mjr 103:dec22cd65b2a 85 // a button when the needle is straight up, but that seems too cumbersome
mjr 103:dec22cd65b2a 86 // for the user, not to mention terribly imprecise. So we'll approach this
mjr 103:dec22cd65b2a 87 // from the other direction: we'll assume a particular placement of the
mjr 103:dec22cd65b2a 88 // rotation point relative to the travel range, and we'll provide
mjr 103:dec22cd65b2a 89 // installation instructions to achieve that assumed alignment.
mjr 100:1ff35c07217c 90 //
mjr 100:1ff35c07217c 91 // The full range we actually have after calibration consists of the park
mjr 100:1ff35c07217c 92 // position and the maximum retracted position. We could in principle also
mjr 100:1ff35c07217c 93 // calibrate the maximum forward position, but that can't be read as reliably
mjr 100:1ff35c07217c 94 // as the other two, because the barrel spring makes it difficult for the
mjr 100:1ff35c07217c 95 // user to be sure they've pushed it all the way forward. Since we can
mjr 100:1ff35c07217c 96 // extract the information we need from the park and max retract positions,
mjr 100:1ff35c07217c 97 // it's better to rely on those alone and not ask for information that the
mjr 100:1ff35c07217c 98 // user can't as easily provide. Given these positions, AND the assumption
mjr 100:1ff35c07217c 99 // that the rotation point is at the midpoint of the plunger travel range,
mjr 103:dec22cd65b2a 100 // we can do some grungy trig work to come up with a formula for the angle
mjr 103:dec22cd65b2a 101 // between the park position and the vertical:
mjr 100:1ff35c07217c 102 //
mjr 100:1ff35c07217c 103 // let C1 = 1 1/32" (distance from midpoint to park),
mjr 100:1ff35c07217c 104 // C2 = 1 17/32" (distance from midpoint to max retract),
mjr 100:1ff35c07217c 105 // C = C2/C1 = 1.48484849,
mjr 100:1ff35c07217c 106 // alpha = angle from park to vertical,
mjr 100:1ff35c07217c 107 // beta = angle from max retract to vertical
mjr 100:1ff35c07217c 108 // theta = alpha + beta = angle from park to max retract, known from calibration,
mjr 100:1ff35c07217c 109 // T = tan(theta);
mjr 100:1ff35c07217c 110 //
mjr 100:1ff35c07217c 111 // then
mjr 100:1ff35c07217c 112 // alpha = atan(sqrt(4*T*T*C + C^2 + 2*C + 1) - C - 1)/(2*T*C))
mjr 100:1ff35c07217c 113 //
mjr 103:dec22cd65b2a 114 // Did I mention this was grungy? At any rate, everything going into that
mjr 103:dec22cd65b2a 115 // last equation is either constant or known from the calibration, so we
mjr 103:dec22cd65b2a 116 // can pre-compute alpha and store it after each calibration operation.
mjr 103:dec22cd65b2a 117 // And once we've computed alpha, we can easily translate an angle reading
mjr 103:dec22cd65b2a 118 // from the sensor to an angle relative to the vertical, which we can plug
mjr 103:dec22cd65b2a 119 // into D*tan(angle) to convert to a linear position on the plunger axis.
mjr 103:dec22cd65b2a 120 //
mjr 103:dec22cd65b2a 121 // The final step is to scale that linear position into joystick reporting
mjr 103:dec22cd65b2a 122 // units. Those units are arbitrary, so we don't have to relate this to any
mjr 103:dec22cd65b2a 123 // real-world lengths. We can simply figure a scaling factor that maps the
mjr 103:dec22cd65b2a 124 // physical range to map to roughly the full range of the joystick units.
mjr 100:1ff35c07217c 125 //
mjr 100:1ff35c07217c 126 // If you're wondering how we derived that ugly formula, read on. Start
mjr 100:1ff35c07217c 127 // with the basic relationships D*tan(alpha) = C1 and D*tan(beta) = C2.
mjr 100:1ff35c07217c 128 // This lets us write tan(beta) in terms of tan(alpha) as
mjr 100:1ff35c07217c 129 // C2/C1*tan(alpha) = C*tan(alpha). We can combine this with an identity
mjr 100:1ff35c07217c 130 // for the tan of a sum of angles:
mjr 100:1ff35c07217c 131 //
mjr 100:1ff35c07217c 132 // tan(alpha + beta) = (tan(alpha) + tan(beta))/(1 - tan(alpha)*tan(beta))
mjr 100:1ff35c07217c 133 //
mjr 100:1ff35c07217c 134 // to obtain:
mjr 100:1ff35c07217c 135 //
mjr 100:1ff35c07217c 136 // tan(theta) = tan(alpha + beta) = (1 + C*tan(alpha))/(1 - C*tan^2(alpha))
mjr 100:1ff35c07217c 137 //
mjr 100:1ff35c07217c 138 // Everything here except alpha is known, so we now have a quadratic equation
mjr 100:1ff35c07217c 139 // for tan(alpha). We can solve that by cranking through the normal algorithm
mjr 100:1ff35c07217c 140 // for solving a quadratic equation, arriving at the solution above.
mjr 100:1ff35c07217c 141 //
mjr 100:1ff35c07217c 142 //
mjr 100:1ff35c07217c 143 // Choosing an install position
mjr 100:1ff35c07217c 144 //
mjr 100:1ff35c07217c 145 // There are two competing factors in choosing the optimal "D". On the one
mjr 100:1ff35c07217c 146 // hand, you'd like D to be as large as possible, to maximum linearity of the
mjr 100:1ff35c07217c 147 // tan function used to translate angle to linear position. Higher linearity
mjr 100:1ff35c07217c 148 // gives us greater immunity to variations in the precise centering of the
mjr 103:dec22cd65b2a 149 // rotation axis in the plunger travel range. tan() is pretty linear (that
mjr 103:dec22cd65b2a 150 // is, tan(theta) is approximately proportional to theta) for small theta,
mjr 103:dec22cd65b2a 151 // within about +/- 30 degrees. On the other hand, you'd like D to be as
mjr 103:dec22cd65b2a 152 // small as possible so that we get the largest overall angle range. Our
mjr 103:dec22cd65b2a 153 // sensor has a fixed angular resolution, so the more of the overall circle
mjr 103:dec22cd65b2a 154 // we use, the more sensor increments we have over the range, and thus the
mjr 103:dec22cd65b2a 155 // better effective linear resolution.
mjr 100:1ff35c07217c 156 //
mjr 100:1ff35c07217c 157 // Let's do some calculations for various "D" values (vertical distance
mjr 103:dec22cd65b2a 158 // between rotation point and plunger rod). We'll base our calculations
mjr 103:dec22cd65b2a 159 // on the AEAT-6012 sensor's 12-bit angular resolution.
mjr 100:1ff35c07217c 160 //
mjr 100:1ff35c07217c 161 // D theta(max) eff dpi theta(park)
mjr 100:1ff35c07217c 162 // -----------------------------------------------
mjr 100:1ff35c07217c 163 // 1 17/32" 45 deg 341 34 deg
mjr 100:1ff35c07217c 164 // 2" 37 deg 280 27 deg
mjr 100:1ff35c07217c 165 // 2 21/32" 30 deg 228 21 deg
mjr 100:1ff35c07217c 166 // 3 1/4" 25 deg 190 17 deg
mjr 100:1ff35c07217c 167 // 4 3/16" 20 deg 152 14 deg
mjr 100:1ff35c07217c 168 //
mjr 100:1ff35c07217c 169 // I'd consider 50 dpi to be the minimum for acceptable performance, 100 dpi
mjr 100:1ff35c07217c 170 // to be excellent, and anything above 300 dpi to be diminishing returns. So
mjr 100:1ff35c07217c 171 // for a 12-bit sensor, 2" looks like the sweet spot. It doesn't take us far
mjr 100:1ff35c07217c 172 // outside of the +/-30 deg zone of tan() linearity, and it achieves almost
mjr 100:1ff35c07217c 173 // 300 dpi of effective linear resolution. I'd stop there are not try to
mjr 100:1ff35c07217c 174 // push the angular resolution higher with a shorter D; with the 45 deg
mjr 100:1ff35c07217c 175 // theta(max) at D = 1-17/32", we'd get a lovely DPI level of 341, but at
mjr 100:1ff35c07217c 176 // the cost of getting pretty non-linear around the ends of the plunger
mjr 100:1ff35c07217c 177 // travel. Our math corrects for the non-linearity, but the more of that
mjr 100:1ff35c07217c 178 // correction we need, the more sensitive the whole contraption becomes to
mjr 100:1ff35c07217c 179 // getting the sensor positioning exactly right. The closer we can stay to
mjr 100:1ff35c07217c 180 // the linear approximation, the more tolerant we are of inexact sensor
mjr 100:1ff35c07217c 181 // positioning.
mjr 100:1ff35c07217c 182 //
mjr 100:1ff35c07217c 183 //
mjr 100:1ff35c07217c 184 // Supported sensors
mjr 100:1ff35c07217c 185 //
mjr 100:1ff35c07217c 186 // * AEAT-6012-A06. This is a magnetic absolute encoder with 12-bit
mjr 100:1ff35c07217c 187 // resolution. It linearly encodes one full (360 degree) rotation in
mjr 100:1ff35c07217c 188 // 4096 increments, so each increment represents 360/4096 = .088 degrees.
mjr 100:1ff35c07217c 189 //
mjr 100:1ff35c07217c 190 // The base class doesn't actually care much about the sensor type; all it
mjr 100:1ff35c07217c 191 // needs from the sensor is an angle reading represented on an arbitrary
mjr 100:1ff35c07217c 192 // linear scale. ("Linear" in the angle, so that one increment represents
mjr 100:1ff35c07217c 193 // a fixed number of degrees of arc. The full scale can represent one full
mjr 100:1ff35c07217c 194 // turn but doesn't have to, as long as the scale is linear over the range
mjr 100:1ff35c07217c 195 // covered.) To add new sensor types, you just need to add the code to
mjr 100:1ff35c07217c 196 // interface to the physical sensor and return its reading on an arbitrary
mjr 100:1ff35c07217c 197 // linear scale.
mjr 100:1ff35c07217c 198
mjr 100:1ff35c07217c 199 #ifndef _ROTARYSENSOR_H_
mjr 100:1ff35c07217c 200 #define _ROTARYSENSOR_H_
mjr 100:1ff35c07217c 201
mjr 100:1ff35c07217c 202 #include "FastInterruptIn.h"
mjr 100:1ff35c07217c 203 #include "AEAT6012.h"
mjr 100:1ff35c07217c 204
mjr 100:1ff35c07217c 205 // The conversion from raw sensor reading to linear position involves a
mjr 100:1ff35c07217c 206 // bunch of translations to different scales and unit systems. To help
mjr 100:1ff35c07217c 207 // keep things straight, let's give each scale a name:
mjr 100:1ff35c07217c 208 //
mjr 100:1ff35c07217c 209 // * "Raw" refers to the readings directly from the sensor. These are
mjr 103:dec22cd65b2a 210 // unsigned ints in the range 0..maxRawAngle, and represent angles in a
mjr 102:41d49e78c253 211 // unit system where one increment equals 360/maxRawAngle degrees. The
mjr 100:1ff35c07217c 212 // zero point is arbitrary, determined by the physical orientation
mjr 100:1ff35c07217c 213 // of the sensor.
mjr 100:1ff35c07217c 214 //
mjr 100:1ff35c07217c 215 // * "Biased" refers to angular units with a zero point equal to the
mjr 103:dec22cd65b2a 216 // park position. This uses the same unit size as the "raw" system, but
mjr 100:1ff35c07217c 217 // the zero point is adjusted so that 0 always means the park position.
mjr 100:1ff35c07217c 218 // Negative values are forward of the park position. This scale is
mjr 100:1ff35c07217c 219 // also adjusted for wrapping, by ensuring that the value lies in the
mjr 100:1ff35c07217c 220 // range -(maximum forward excursion) to +(scale max - max fwd excursion).
mjr 100:1ff35c07217c 221 // Any values below or above the range are bumped up or down (respectively)
mjr 100:1ff35c07217c 222 // to wrap them back into the range.
mjr 100:1ff35c07217c 223 //
mjr 100:1ff35c07217c 224 // * "Linear" refers to the final linear results, in joystick units, on
mjr 100:1ff35c07217c 225 // the abstract integer scale from 0..65535 used by the generic plunger
mjr 100:1ff35c07217c 226 // base class.
mjr 100:1ff35c07217c 227 //
mjr 100:1ff35c07217c 228 class PlungerSensorRotary: public PlungerSensor
mjr 100:1ff35c07217c 229 {
mjr 100:1ff35c07217c 230 public:
mjr 102:41d49e78c253 231 PlungerSensorRotary(int maxRawAngle, float radiansPerSensorUnit) :
mjr 100:1ff35c07217c 232 PlungerSensor(65535),
mjr 102:41d49e78c253 233 maxRawAngle(maxRawAngle),
mjr 100:1ff35c07217c 234 radiansPerSensorUnit(radiansPerSensorUnit)
mjr 100:1ff35c07217c 235 {
mjr 100:1ff35c07217c 236 // start our sample timer with an arbitrary zero point of now
mjr 100:1ff35c07217c 237 timer.start();
mjr 100:1ff35c07217c 238
mjr 100:1ff35c07217c 239 // clear the timing statistics
mjr 100:1ff35c07217c 240 nReads = 0;
mjr 100:1ff35c07217c 241 totalReadTime = 0;
mjr 100:1ff35c07217c 242
mjr 100:1ff35c07217c 243 // Pre-calculate the maximum forward excursion distance, in raw
mjr 100:1ff35c07217c 244 // units. For our reference mechanical setup with "D" in a likely
mjr 100:1ff35c07217c 245 // range, theta(max) is always about 10 degrees higher than
mjr 100:1ff35c07217c 246 // theta(park). 10 degrees is about 1/36 of the overall circle,
mjr 100:1ff35c07217c 247 // which is the same as 1/36 of the sensor scale. To be
mjr 100:1ff35c07217c 248 // conservative, allow for about 3X that, so allow 1/12 of scale
mjr 100:1ff35c07217c 249 // as the maximum forward excursion. For wrapping purposes, we'll
mjr 100:1ff35c07217c 250 // consider any reading outside of the range from -(excursion)
mjr 102:41d49e78c253 251 // to +(maxRawAngle - excursion) to be wrapped.
mjr 102:41d49e78c253 252 maxForwardExcursionRaw = maxRawAngle/12;
mjr 100:1ff35c07217c 253
mjr 100:1ff35c07217c 254 // reset the calibration counters
mjr 100:1ff35c07217c 255 biasedMinObserved = biasedMaxObserved = 0;
mjr 100:1ff35c07217c 256 }
mjr 100:1ff35c07217c 257
mjr 100:1ff35c07217c 258 // Restore the saved calibration at startup
mjr 100:1ff35c07217c 259 virtual void restoreCalibration(Config &cfg)
mjr 100:1ff35c07217c 260 {
mjr 100:1ff35c07217c 261 // only proceed if there's calibration data to retrieve
mjr 100:1ff35c07217c 262 if (cfg.plunger.cal.calibrated)
mjr 100:1ff35c07217c 263 {
mjr 100:1ff35c07217c 264 // we store the raw park angle in raw0
mjr 100:1ff35c07217c 265 rawParkAngle = cfg.plunger.cal.raw0;
mjr 100:1ff35c07217c 266
mjr 100:1ff35c07217c 267 // we store biased max angle in raw1
mjr 100:1ff35c07217c 268 biasedMax = cfg.plunger.cal.raw1;
mjr 100:1ff35c07217c 269 }
mjr 100:1ff35c07217c 270 else
mjr 100:1ff35c07217c 271 {
mjr 100:1ff35c07217c 272 // Use the current sensor reading as the initial guess at the
mjr 100:1ff35c07217c 273 // park position. The system is usually powered up with the
mjr 100:1ff35c07217c 274 // plunger at the neutral position, so this is a good guess in
mjr 100:1ff35c07217c 275 // most cases. If the plunger has been calibrated, we'll restore
mjr 100:1ff35c07217c 276 // the better guess when we restore the configuration later on in
mjr 100:1ff35c07217c 277 // the initialization process.
mjr 100:1ff35c07217c 278 rawParkAngle = 0;
mjr 100:1ff35c07217c 279 readSensor(rawParkAngle);
mjr 100:1ff35c07217c 280
mjr 100:1ff35c07217c 281 // Set an initial wild guess at a range equal to +/-35 degrees.
mjr 100:1ff35c07217c 282 // Note that this is in the "biased" coordinate system - raw
mjr 100:1ff35c07217c 283 // units, but relative to the park angle. The park angle is
mjr 102:41d49e78c253 284 // about -25 degrees in this setup.
mjr 102:41d49e78c253 285 biasedMax = (35 + 25) * maxRawAngle/360;
mjr 100:1ff35c07217c 286 }
mjr 100:1ff35c07217c 287
mjr 100:1ff35c07217c 288 // recalculate the vertical angle
mjr 100:1ff35c07217c 289 updateAlpha();
mjr 100:1ff35c07217c 290 }
mjr 100:1ff35c07217c 291
mjr 100:1ff35c07217c 292 // Begin calibration
mjr 100:1ff35c07217c 293 virtual void beginCalibration(Config &)
mjr 100:1ff35c07217c 294 {
mjr 100:1ff35c07217c 295 // Calibration starts out with the plunger at the park position, so
mjr 100:1ff35c07217c 296 // we can take the current sensor reading to be the park position.
mjr 100:1ff35c07217c 297 rawParkAngle = 0;
mjr 100:1ff35c07217c 298 readSensor(rawParkAngle);
mjr 100:1ff35c07217c 299
mjr 100:1ff35c07217c 300 // Reset the observed calibration counters
mjr 100:1ff35c07217c 301 biasedMinObserved = biasedMaxObserved = 0;
mjr 100:1ff35c07217c 302 }
mjr 100:1ff35c07217c 303
mjr 100:1ff35c07217c 304 // End calibration
mjr 100:1ff35c07217c 305 virtual void endCalibration(Config &cfg)
mjr 100:1ff35c07217c 306 {
mjr 100:1ff35c07217c 307 // apply the observed maximum angle
mjr 100:1ff35c07217c 308 biasedMax = biasedMaxObserved;
mjr 100:1ff35c07217c 309
mjr 100:1ff35c07217c 310 // recalculate the vertical angle
mjr 100:1ff35c07217c 311 updateAlpha();
mjr 100:1ff35c07217c 312
mjr 100:1ff35c07217c 313 // save our raw configuration data
mjr 100:1ff35c07217c 314 cfg.plunger.cal.raw0 = static_cast<uint16_t>(rawParkAngle);
mjr 100:1ff35c07217c 315 cfg.plunger.cal.raw1 = static_cast<uint16_t>(biasedMax);
mjr 100:1ff35c07217c 316
mjr 100:1ff35c07217c 317 // Refigure the range for the generic code
mjr 100:1ff35c07217c 318 cfg.plunger.cal.min = biasedAngleToLinear(biasedMinObserved);
mjr 100:1ff35c07217c 319 cfg.plunger.cal.max = biasedAngleToLinear(biasedMaxObserved);
mjr 100:1ff35c07217c 320 cfg.plunger.cal.zero = biasedAngleToLinear(0);
mjr 100:1ff35c07217c 321 }
mjr 100:1ff35c07217c 322
mjr 100:1ff35c07217c 323 // figure the average scan time in microseconds
mjr 100:1ff35c07217c 324 virtual uint32_t getAvgScanTime()
mjr 100:1ff35c07217c 325 {
mjr 100:1ff35c07217c 326 return nReads == 0 ? 0 : static_cast<uint32_t>(totalReadTime / nReads);
mjr 100:1ff35c07217c 327 }
mjr 100:1ff35c07217c 328
mjr 100:1ff35c07217c 329 // read the sensor
mjr 100:1ff35c07217c 330 virtual bool readRaw(PlungerReading &r)
mjr 100:1ff35c07217c 331 {
mjr 100:1ff35c07217c 332 // note the starting time for the reading
mjr 100:1ff35c07217c 333 uint32_t t0 = timer.read_us();
mjr 100:1ff35c07217c 334
mjr 100:1ff35c07217c 335 // read the angular position
mjr 100:1ff35c07217c 336 int angle;
mjr 100:1ff35c07217c 337 if (!readSensor(angle))
mjr 100:1ff35c07217c 338 return false;
mjr 102:41d49e78c253 339
mjr 100:1ff35c07217c 340 // Refigure the angle relative to the raw park position. This
mjr 100:1ff35c07217c 341 // is the "biased" angle.
mjr 100:1ff35c07217c 342 angle -= rawParkAngle;
mjr 100:1ff35c07217c 343
mjr 100:1ff35c07217c 344 // Adjust for wrapping.
mjr 100:1ff35c07217c 345 //
mjr 100:1ff35c07217c 346 // An angular sensor reports the position on a circular scale, for
mjr 100:1ff35c07217c 347 // obvious reasons, so there's some point along the circle where the
mjr 100:1ff35c07217c 348 // angle is zero. One tick before that point reads as the maximum
mjr 100:1ff35c07217c 349 // angle on the scale, so we say that the scale "wraps" at that point.
mjr 100:1ff35c07217c 350 //
mjr 100:1ff35c07217c 351 // To correct for this, we can look to the layout of the mechanical
mjr 100:1ff35c07217c 352 // setup to constrain the values. Consider anything below the maximum
mjr 100:1ff35c07217c 353 // forward exclusion to be wrapped on the low side, and consider
mjr 100:1ff35c07217c 354 // anything outside of the complementary range on the high side to
mjr 100:1ff35c07217c 355 // be wrapped on the high side.
mjr 102:41d49e78c253 356 if (angle < -maxForwardExcursionRaw)
mjr 102:41d49e78c253 357 angle += maxRawAngle;
mjr 102:41d49e78c253 358 else if (angle >= maxRawAngle - maxForwardExcursionRaw)
mjr 102:41d49e78c253 359 angle -= maxRawAngle;
mjr 100:1ff35c07217c 360
mjr 100:1ff35c07217c 361 // Note if this is the highest/lowest observed reading on the biased
mjr 100:1ff35c07217c 362 // scale since the last calibration started.
mjr 100:1ff35c07217c 363 if (angle > biasedMaxObserved)
mjr 100:1ff35c07217c 364 biasedMaxObserved = angle;
mjr 100:1ff35c07217c 365 if (angle < biasedMinObserved)
mjr 100:1ff35c07217c 366 biasedMinObserved = angle;
mjr 100:1ff35c07217c 367
mjr 100:1ff35c07217c 368 // figure the linear result
mjr 100:1ff35c07217c 369 r.pos = biasedAngleToLinear(angle);
mjr 102:41d49e78c253 370
mjr 100:1ff35c07217c 371 // Set the timestamp on the reading to right now
mjr 100:1ff35c07217c 372 uint32_t now = timer.read_us();
mjr 100:1ff35c07217c 373 r.t = now;
mjr 100:1ff35c07217c 374
mjr 100:1ff35c07217c 375 // count the read statistics
mjr 100:1ff35c07217c 376 totalReadTime += now - t0;
mjr 100:1ff35c07217c 377 nReads += 1;
mjr 100:1ff35c07217c 378
mjr 100:1ff35c07217c 379 // success
mjr 100:1ff35c07217c 380 return true;
mjr 100:1ff35c07217c 381 }
mjr 100:1ff35c07217c 382
mjr 100:1ff35c07217c 383 private:
mjr 100:1ff35c07217c 384 // Read the underlying sensor - implemented by the hardware-specific
mjr 100:1ff35c07217c 385 // subclasses. Returns true on success, false if the sensor can't
mjr 100:1ff35c07217c 386 // be read. The angle is returned in raw sensor units.
mjr 100:1ff35c07217c 387 virtual bool readSensor(int &angle) = 0;
mjr 100:1ff35c07217c 388
mjr 100:1ff35c07217c 389 // Convert a biased angle value to a linear reading
mjr 100:1ff35c07217c 390 int biasedAngleToLinear(int angle)
mjr 100:1ff35c07217c 391 {
mjr 100:1ff35c07217c 392 // Translate to an angle relative to the vertical, in sensor units
mjr 102:41d49e78c253 393 float theta = static_cast<float>(angle)*radiansPerSensorUnit - alpha;
mjr 100:1ff35c07217c 394
mjr 102:41d49e78c253 395 // Calculate the linear position relative to the vertical. Zero
mjr 102:41d49e78c253 396 // is right at the intersection of the vertical line from the
mjr 102:41d49e78c253 397 // sensor rotation center to the plunger axis; positive numbers
mjr 102:41d49e78c253 398 // are behind the vertical (more retracted).
mjr 102:41d49e78c253 399 int linearPos = static_cast<int>(tanf(theta) * linearScaleFactor);
mjr 100:1ff35c07217c 400
mjr 102:41d49e78c253 401 // Finally, figure the offset. The vertical is the halfway point
mjr 102:41d49e78c253 402 // of the plunger motion, so we want to put it at half of the raw
mjr 102:41d49e78c253 403 // scale of 0..65535.
mjr 102:41d49e78c253 404 return linearPos + 32767;
mjr 100:1ff35c07217c 405 }
mjr 100:1ff35c07217c 406
mjr 100:1ff35c07217c 407 // Update the estimation of the vertical angle, based on the angle
mjr 100:1ff35c07217c 408 // between the park position and maximum retraction point.
mjr 100:1ff35c07217c 409 void updateAlpha()
mjr 100:1ff35c07217c 410 {
mjr 100:1ff35c07217c 411 // See the comments at the top of the file for details on this
mjr 100:1ff35c07217c 412 // formula. This figures the angle between the park position
mjr 100:1ff35c07217c 413 // and the vertical by applying the known constraints of the
mjr 100:1ff35c07217c 414 // mechanical setup: the known length of a standard plunger,
mjr 100:1ff35c07217c 415 // and the requirement that the rotation axis be placed at
mjr 100:1ff35c07217c 416 // roughly the midpoint of the plunger travel.
mjr 100:1ff35c07217c 417 const float C = 1.4848489f; // 1-17/32" / 1-1/32"
mjr 102:41d49e78c253 418 float maxInRadians = static_cast<float>(biasedMax) * radiansPerSensorUnit;
mjr 102:41d49e78c253 419 float T = tanf(maxInRadians);
mjr 102:41d49e78c253 420 alpha = atanf((sqrtf(4*T*T*C + C*C + 2*C + 1) - C - 1)/(2*T*C));
mjr 102:41d49e78c253 421
mjr 102:41d49e78c253 422 // While we're at it, figure the linear conversion factor. Alpha
mjr 102:41d49e78c253 423 // represents the angle from the park position to the midpoint,
mjr 102:41d49e78c253 424 // which in the real world represents about 31/32", or just less
mjr 102:41d49e78c253 425 // then 1/3 of the overall travel. We want to normalize this to
mjr 102:41d49e78c253 426 // the corresponding fraction of our 0..65535 abstract linear unit
mjr 102:41d49e78c253 427 // system. To avoid overflow, normalize to a slightly smaller
mjr 102:41d49e78c253 428 // scale.
mjr 100:1ff35c07217c 429 const float safeMax = 60000.0f;
mjr 102:41d49e78c253 430 const float alphaInLinearUnits = safeMax * .316327f; // 31/22" / 3-1/16"
mjr 102:41d49e78c253 431 linearScaleFactor = static_cast<int>(alphaInLinearUnits / tanf(alpha));
mjr 100:1ff35c07217c 432 }
mjr 100:1ff35c07217c 433
mjr 100:1ff35c07217c 434 // Maximum raw angular reading from the sensor. The sensor's readings
mjr 102:41d49e78c253 435 // will always be on a scale from 0..maxRawAngle.
mjr 102:41d49e78c253 436 int maxRawAngle;
mjr 100:1ff35c07217c 437
mjr 100:1ff35c07217c 438 // Radians per sensor unit. This is a constant for the sensor.
mjr 100:1ff35c07217c 439 float radiansPerSensorUnit;
mjr 100:1ff35c07217c 440
mjr 100:1ff35c07217c 441 // Pre-calculated value of the maximum forward excursion, in raw units.
mjr 102:41d49e78c253 442 int maxForwardExcursionRaw;
mjr 100:1ff35c07217c 443
mjr 100:1ff35c07217c 444 // Raw reading at the park position. We use this to handle "wrapping",
mjr 100:1ff35c07217c 445 // if the sensor's raw zero reading position is within the plunger travel
mjr 100:1ff35c07217c 446 // range. All readings are taken to be within
mjr 100:1ff35c07217c 447 int rawParkAngle;
mjr 100:1ff35c07217c 448
mjr 100:1ff35c07217c 449 // Biased maximum angle. This is the angle at the maximum retracted
mjr 100:1ff35c07217c 450 // position, in biased units (sensor units, relative to the park angle).
mjr 100:1ff35c07217c 451 int biasedMax;
mjr 100:1ff35c07217c 452
mjr 100:1ff35c07217c 453 // Mininum and maximum angle observed since last calibration start, on
mjr 100:1ff35c07217c 454 // the biased scale
mjr 100:1ff35c07217c 455 int biasedMinObserved;
mjr 100:1ff35c07217c 456 int biasedMaxObserved;
mjr 100:1ff35c07217c 457
mjr 100:1ff35c07217c 458 // The "alpha" angle - the angle between the park position and the
mjr 100:1ff35c07217c 459 // vertical line between the rotation axis and the plunger. This is
mjr 102:41d49e78c253 460 // represented in radians.
mjr 102:41d49e78c253 461 float alpha;
mjr 100:1ff35c07217c 462
mjr 100:1ff35c07217c 463 // The linear scaling factor, applied in our trig calculation from
mjr 100:1ff35c07217c 464 // angle to linear position. This corresponds to the distance from
mjr 100:1ff35c07217c 465 // the rotation center to the plunger rod, but since the linear result
mjr 100:1ff35c07217c 466 // is in abstract joystick units, this distance is likewise in abstract
mjr 100:1ff35c07217c 467 // units. The value isn't chosen to correspond to any real-world
mjr 100:1ff35c07217c 468 // distance units, but rather to yield a joystick result that takes
mjr 100:1ff35c07217c 469 // advantage of most of the available axis range, to minimize rounding
mjr 100:1ff35c07217c 470 // errors when converting between scales.
mjr 100:1ff35c07217c 471 float linearScaleFactor;
mjr 100:1ff35c07217c 472
mjr 100:1ff35c07217c 473 // timer for input timestamps and read timing measurements
mjr 100:1ff35c07217c 474 Timer timer;
mjr 100:1ff35c07217c 475
mjr 100:1ff35c07217c 476 // read timing statistics
mjr 100:1ff35c07217c 477 uint64_t totalReadTime;
mjr 100:1ff35c07217c 478 uint64_t nReads;
mjr 100:1ff35c07217c 479
mjr 100:1ff35c07217c 480 // Keep track of when calibration is in progress. The calibration
mjr 100:1ff35c07217c 481 // procedure is usually handled by the generic main loop code, but
mjr 100:1ff35c07217c 482 // in this case, we have to keep track of some of the raw sensor
mjr 100:1ff35c07217c 483 // data during calibration for our own internal purposes.
mjr 100:1ff35c07217c 484 bool calibrating;
mjr 100:1ff35c07217c 485 };
mjr 100:1ff35c07217c 486
mjr 100:1ff35c07217c 487 // Specialization for the AEAT-601X sensors
mjr 100:1ff35c07217c 488 template<int nDataBits> class PlungerSensorAEAT601X : public PlungerSensorRotary
mjr 100:1ff35c07217c 489 {
mjr 100:1ff35c07217c 490 public:
mjr 100:1ff35c07217c 491 PlungerSensorAEAT601X(PinName csPin, PinName clkPin, PinName doPin) :
mjr 100:1ff35c07217c 492 PlungerSensorRotary((1 << nDataBits) - 1, 6.283185f/((1 << nDataBits) - 1)),
mjr 100:1ff35c07217c 493 aeat(csPin, clkPin, doPin)
mjr 100:1ff35c07217c 494 {
mjr 100:1ff35c07217c 495 // Make sure the sensor has had time to finish initializing.
mjr 100:1ff35c07217c 496 // Power-up time (tCF) from the data sheet is 20ms for the 12-bit
mjr 100:1ff35c07217c 497 // version, 50ms for the 10-bit version.
mjr 100:1ff35c07217c 498 wait_ms(nDataBits == 12 ? 20 :
mjr 100:1ff35c07217c 499 nDataBits == 10 ? 50 :
mjr 100:1ff35c07217c 500 50);
mjr 100:1ff35c07217c 501 }
mjr 100:1ff35c07217c 502
mjr 100:1ff35c07217c 503 // read the angle
mjr 100:1ff35c07217c 504 virtual bool readSensor(int &angle)
mjr 100:1ff35c07217c 505 {
mjr 100:1ff35c07217c 506 angle = aeat.readAngle();
mjr 100:1ff35c07217c 507 return true;
mjr 100:1ff35c07217c 508 }
mjr 100:1ff35c07217c 509
mjr 100:1ff35c07217c 510 protected:
mjr 100:1ff35c07217c 511 // physical sensor interface
mjr 100:1ff35c07217c 512 AEAT601X<nDataBits> aeat;
mjr 100:1ff35c07217c 513 };
mjr 100:1ff35c07217c 514
mjr 100:1ff35c07217c 515 #endif